Deposition/erosion measurements by means of a Quartz Micro Balance (QMB) located below the Load Bearing Septum Replacement Plate in the private flux region of the inner divertor of JET (with full carbon wall) revealed net deposition with the inner strike point located on the vertical tile and net erosion with the inner strike point on the horizontal tile [H.G. Esser et al., J. Nucl. Mater. 390–391, 148 (2009)]. ERO calculations show about 3.5 times larger flux entering the QMB aperture when the inner strike point is located on the vertical plate compared to the case when strike point is on the horizontal plate – thus indicating similar behavior. Using these fluxes from ERO as input, detailed modeling of erosion/deposition at the QMB itself considering the realistic geometry of the QMB housing has been performed with the 3D-GAPS code. The QMB measurements can be reproduced with combined ERO/3D-GAPS modeling if erosion due to deuterium atoms within the QMB housing is taken into account.